To investigate further the relevance of FOXO3 methylation in repressing FOXO3 expression in basal breast cancer, the basal-type cell lines HCC70 and MDA-MB-468, and the luminal-type cell line MCF-7 were treated with different amounts of 5′-aza-dC (0, 1 and 5 μM) for 72 h, and BRCA1, FOXO3 and EZH2 expression levels examined by both western blotting and quantitative reverse-transcriptase PCR (qRT–PCR). The gene discussed is BRCA1; the disease is breast carcinoma.